The present invention relates to a conduit box and a method of installing conduit into the conduit box. In particular, the present invention relates to a conduit box that improves conduit installation by disposing conduit free of offsets near the conduit box during installation.
In typical construction installations, conduits, such as electrical conduit, mechanical conduit and tubing, are installed to a roof deck wherein the roof deck comprises a corrugated channel. Typically, the square shaped conduit boxes are fastened to the bottom of the corrugated channel while the conduit is disposed within the channel. This configuration, however, requires that each conduit offset once to enter the conduit box and offset once again to exit the conduit box since the conduit box is fastened below the corrugated channel.
Accordingly, in present commercial conduit boxes, the installation requires numerous labor steps and material consumption due to the offsets required. In a typical installation, the installer fastens the conduit box to the bottom of the corrugated channel and installs conduit through the corrugated channel up to the conduit box. Next, the installer must measure the offset between each conduit and the conduit box. The installer then processes a piece of conduit or fitting through a bending machine to produce a conduit piece/fitting matching the offset dimension required. Next, the installer connects the conduit piece/fitting to the conduit and the conduit box via the conduit piece/fitting. After connecting the conduit to the side of the conduit box, the installer repeats the process for the other side of the conduit box.
Typically, the installer must move between the elevated conduit box and the grounded bending machine which requires the installer to climb a ladder or to harness into a lift for each move between the conduit box and the bending machine. Alternatively, the bending machine may be elevated with the installer. This configuration, though, still requires additional back and forth steps of processing the offsets. Accordingly, the offsets increase the labor steps and material consumption. Additionally, the offsets increase the difficulty of pulling wire through the conduit since the wire can become jammed, i.e. a “bottleneck”, at each offset. Furthermore, the National Electrical Code limits the number of offsets in a conduit run:                358.62 Bends—Number In One Run: “There shall not be more than the equivalent of four quarter bends (360° total) between pull points, for example, conduit bodies and boxes.” (National Electrical Code 2002).        
In a typical installation, the installer uses two 30° bends to make an offset wherein one offset equals 60° of bend. Accordingly, an offset entering the conduit box and an offset exiting a conduit box equals 120°. Therefore, almost one third of the allowable bends are accumulated at one conduit box.
When the installer positions the conduit box against the corrugated channel, the installer fastens the conduit box to the corrugated channel via fasteners such as screws. In a typical installation, the conduit box requires a separate support structure such as uni-strut when the conduit box supports fixtures or fans.
Efficiently and quickly installing conduit is essential for today's fast paced/turn key construction projects. Multiple labor steps and material consumption experienced in typical construction leads to costly and time consuming installation. Accordingly, an installer must work faster leading to increased safety risks and poor quality installations.
Thus, a need exists for an improved method of installing conduits. The solution, though, must eliminate costly labor steps and material consumption. The solution must also improve efficiency while maintaining safety standards. The solution, however, must provide a convenient method of easily disposing conduit and pulling wire through the conduit. Thus, a need exists to provide an efficient connection to the disposed conduit which eliminates offsets between the conduit box and the disposed conduit. A need also exists for installing conduit boxes without extra supports. The solution, though, must provide for a substantial load capacity such as a ceiling fan. Additionally, a need exists for an efficient method of manufacturing an improved conduit box. The prior art fails to meet the needs since the prior art does not efficiently eliminate labor steps and material consumption.
U.S. Pat. No. 4,634,015 issued to Taylor discloses an adjustable electrical box attachment for use on conventional electrical junction boxes. The box includes a mounting plate and a collar, open at the front and rear ends, disposed on a mounting plate about a central opening. The mounting plate is positioned to slide forward and reward within the collar to contact the sidewalls of the collar to be flush against the sidewalls to properly position a light switch against the wall.
U.S. Pat. No. 5,448,012 issued to Jacob discloses a method of installing electrical conduit between a pair of non adjacent electrical boxes positioned within a wall. The boxes include at least one section of a greater depth than the remainder of the box while the normally interfering box is installed in an inverse orientation with respect to the first box wherein the conduit connecting the pair of non adjacent boxes passes behind the area of lesser depth.
U.S. Pat. No. 5,239,132 issued to Bartow discloses a device for retaining an electrical junction box in flush relationship with a wall or a ceiling with a strip. The ends of the strap are longitudinally bifurcated to provide fingers to be deformed around the edges of the box as well as the outer surface. Wings extending out from a side edge of the strap are used to provide support against the inner wall surface to prevent inward falling of the box or to prevent downward slipping of the box with respect to the wall.
U.S. Pat. No. 6,209,836 issued to Swanson discloses a mounting bracket for supporting an electrical box between a pair of stud walls. The bracket is a one piece, unitary member stamped from sheet metal. The mounting bracket has top support rail, a bottom support rail and a pair of mounting ends coupling the support rails together to define a cutout which prevents vertical movement of the electrical box.
U.S. Pat. No. 6,369,322 issued to Gretz discloses a one piece plastic molded box having an open face member, an open back, an extender positioned coplanar with and extending from the face member and four wings extending from the face member. The extender inserts into an electrical box with the wings flexed toward each other to position the extender flush with the electrical box to form a device insulator.
These prior art devices fail to meet the present needs since the devices are designed to fit between stud walls where boxes will be interfering with each other as opposed to securely mounting a conduit box in corrugated roofing. Additionally, these devices do not eliminate labor steps or eliminate material consumption during conduit installation in corrugated roofing. Further, these devices do not provide efficient mounting for corrugated roofing installation since these devices do not eliminate offsets between the conduit and conduit box. Additionally, these devices are not designed for substantial load support such as ceiling fans and heavy lighting fixtures. Additionally, these devices provide knock outs which are stacked directly upon one another preventing any tightening of upper or back connectors.